Publications (26)92.9 Total impact
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Article: IL-6-mediated Th17 differentiation through RORγt is essential for the initiation of experimental autoimmune myocarditis.
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ABSTRACT: Interleukin (IL)-17-producing helper T (Th17) cells have been proposed to participate in the pathogenesis of chronic inflammation, such as autoimmune myocarditis. IL-6 gene ablation confers the resistance to experimental autoimmune myocarditis (EAM). In this study, we have addressed the pathological roles of IL-6 in the regulation of Th17 cells in EAM. To induce EAM, mice were immunized twice with α-myosin heavy chain peptide. Three weeks after the first injection, the cardiac expression of the Th17-specific transcription factor, retinoic acid receptor-related orphan nuclear receptor (ROR γt), was up-regulated. Consistently, Th17 cells were recruited into EAM hearts, as analysed by flow cytometry. Using the mice with enhanced green fluorescence protein (eGFP) gene knocked-in at RORγt locus (RORγt-eGFP mice), we observed Th17 cell infiltration into inflamed lesions. Pre-treatment with IL-6 receptor (IL-6R)-blocking antibody (anti-IL-6R Ab) inhibited EAM induction in terms of disease severity score (3.5 ± 0.8; IgG vs. 0.5 ± 0.8; anti-IL-6R Ab, n = 6, P< 0.01) and suppressed the myocardial expression of IL-17 and RORγt. In contrast, the administration of anti-IL-6R Ab 7 days after the first immunization failed to show the inhibitory effects, suggesting that IL-6 plays important roles in EAM initiation. Finally, by generating RORγt-eGFP homozygous mice, we revealed that RORγt gene ablation conferred the resistance to EAM induction. IL-6-mediated induction of Th17 cells is critical for the onset of EAM, but not for its progression. IL-6/Th17 signalling could be a promising therapeutic target for the prevention of myocardial inflammation.Cardiovascular research 05/2011; 91(4):640-8. · 5.80 Impact Factor -
Article: Single and local blockade of interleukin-6 signaling promotes neuronal differentiation from transplanted embryonic stem cell-derived neural precursor cells.
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ABSTRACT: Safe and efficient transplantation of embryonic stem (ES) cells to the brain requires that local inflammatory and immune responses to allogeneic grafts are inhibited. To investigate cytokines that affect graft cell survival and differentiation, we used stromal cell-derived inducing activity to induce the differentiation of neural progenitor cells (NPCs) from mouse ES cells and transplanted the NPCs into mouse brain. Examination of surrounding brain tissue revealed elevated expression levels of interleukin (IL)-1β, IL-4, and IL-6 in response to NPC transplantation. Among these, only IL-6 reduced neuronal differentiation and promoted glial differentiation in vitro. When we added anti-IL-6 receptor antibodies to NPCs during transplantation, this single and local blockade of IL-6 signaling reduced the accumulation of host-derived leukocytes, including microglia. Furthermore, it also promoted neuronal differentiation and reduced glial differentiation from the grafted NPCs to an extent similar to that with systemic and continuous administration of cyclosporine A. These results suggest that local administration of anti-IL-6 receptor antibodies with NPCs may promote neuronal differentiation during the treatment of neurological diseases with cell replacement therapy.Journal of Neuroscience Research 05/2011; 89(9):1388-99. · 2.74 Impact Factor -
Article: Comparative analysis of the effects of anti-IL-6 receptor mAb and anti-TNF mAb treatment on CD4+ T-cell responses in murine colitis.
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ABSTRACT: The efficacy of anti-tumor necrosis factor monoclonal antibody (anti-TNF mAb) for Crohn's disease (CD) is well established, and anti-interleukin-6 receptor (anti-IL-6R) mAb has also been reported to be effective in CD. It is, however, unclear if the efficacy and mechanisms of both agents are different in CD therapy. Using an adoptive transfer colitis model, we compared the efficacy of anti-IL-6R mAb, anti-TNF mAb, and TNF receptor-Fc fusion protein (TNFR-Fc), and their modes of action on CD4+ T cells. We also investigated the role of Th1 and Th17 cells in colitis using the same model. The histological scores for the anti-IL-6R mAb and anti-TNF mAb groups but not for TNFR-Fc group were much lower than that for the control group, and the score was the lowest for the anti-IL-6R mAb group. The frequency of proliferating CD4+ T cells was reduced in anti-IL-6R mAb and anti-TNF mAb groups, but not in the TNFR-Fc group, whereas the frequency of apoptotic CD4+ T cells was similar in all groups. Anti-IL-6R mAb suppressed the induction of Th17 cells and increased the frequency of lamina propria regulatory T cells, whereas anti-TNF mAb exerted no influence on CD4+ T-cell differentiation. A deficiency in interferon-γ and/or IL-17 in CD4+ T cells reduced the severity of colitis. Our findings suggest that suppression of the proliferation of pathogenic CD4+ T cells is the major mode of action of biological agents for colitis therapy. Anti-IL-6R mAb might have benefits in CD patients with Th17 dominance and impaired Treg frequency.Inflammatory Bowel Diseases 02/2011; 17(2):491-502. · 4.86 Impact Factor -
Article: Anti-IL-6 receptor antibody causes less promotion of tuberculosis infection than anti-TNF-α antibody in mice.
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ABSTRACT: Objective. Our aim was to investigate the effects of IL-6 blockade on the progression of Mycobacterium tuberculosis (TB) and compare them with those of TNF-α blockade in mice. Methods. Mice were intravenously infected with TB and injected with antibodies. Survival was monitored and histological and immunological studies were carried out. Results. All anti-IL-6R Ab-treated mice and 8 of 10 control mice survived until sacrificed 224 days after TB challenge, whereas anti-TNF-α Ab-treated mice all died between 120 and 181 days. Anti-IL-6R Ab-treated mice exhibited no significant differences in TB CFU in organs, including the lungs, and no deterioration in histopathology compared to control mice at 4 weeks. In contrast, anti-TNF-α Ab-treated mice exhibited increased TB CFU and greater progression of histopathological findings in organs than control mice. Spleen cells from anti-TNF-α Ab-treated mice had decreased antigen-specific response in IFN-γ release and proliferation assays. The results in anti-IL-6R Ab-treated mice suggest that spleen cell responses were decreased to a lesser degree. Similar results were obtained in IL-6 knockout (KO) mice, compared with TNF receptor 1 (TNFR1) KO and TNFR1/IL-6 double KO (DKO) mice. Conclusion. IL-6R blockade promotes the progression of TB infection in mice far less than TNF-α blockade.Clinical and Developmental Immunology 01/2011; 2011:404929. · 1.84 Impact Factor -
Article: Anti-IL-6-receptor antibody promotes repair of spinal cord injury by inducing microglia-dominant inflammation.
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ABSTRACT: We previously reported the beneficial effect of administering an anti-mouse IL-6 receptor antibody (MR16-1) immediately after spinal cord injury (SCI). The purpose of our present study was to clarify the mechanism underlying how MR16-1 improves motor function after SCI. Quantitative analyses of inflammatory cells using flow cytometry, and immunohistochemistry with bone marrow-chimeric mice generated by transplanting genetically marked purified hematopoietic stem cells, revealed that MR16-1 dramatically switched the central player in the post-traumatic inflammation, from hematogenous macrophages to resident microglia. This change was accompanied by alterations in the expression of relevant cytokines within the injured spinal cord; the expression of recruiting chemokines including CCL2, CCL5, and CXCL10 was decreased, while that of Granulocyte/Macrophage-Colony Stimulating Factor (GM-CSF), a known mitogen for microglia, was increased. We also showed that the resident microglia expressed higher levels of phagocytic markers than the hematogenous macrophages. Consistent with these findings, we observed significantly decreased tissue damage and reduced levels of myelin debris and Nogo-A, the axonal growth inhibitor, by MR16-1 treatment. Moreover, we observed increased axonal regeneration and/or sprouting in the MR16-1-treated mice. Our findings indicate that the functional improvement elicited by MR16-1 involves microglial functions, and provide new insights into the role of IL-6 signaling in the pathology of SCI.Experimental Neurology 08/2010; 224(2):403-14. · 4.70 Impact Factor -
Article: Blockade of interleukin-6 signaling suppressed cochlear inflammatory response and improved hearing impairment in noise-damaged mice cochlea.
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ABSTRACT: Hearing impairment can be the cause of serious socio-economic disadvantages. Recent studies have shown inflammatory responses in the inner ear co-occur with various damaging conditions including noise-induced hearing loss. We reported pro-inflammatory cytokine interleukin-6 (IL-6) was induced in the cochlea 6h after noise exposure, but the pathophysiological implications of this are still obscure. To address this issue, we investigated the effects of IL-6 inhibition using the anti-IL-6 receptor antibody (MR16-1). Noise-exposed mice were treated with MR16-1 and evaluated. Improved hearing at 4kHz as measured by auditory brainstem response (ABR) was noted in noise-exposed mice treated with MR16-1. Histological analysis revealed the decrease in spiral ganglion neurons was ameliorated in the MR16-1-treated group, while no significant change was observed in the organ of Corti. Immunohistochemistry for Iba1 and CD45 demonstrated a remarkable reduction of activated cochlear macrophages in spiral ganglions compared to the control group when treated with MR16-1. Thus, MR16-1 had protective effects both functionally and pathologically for the noise-damaged cochlea primarily due to suppression of neuronal loss and presumably through alleviation of inflammatory responses. Anti-inflammatory cytokine therapy including IL-6 blockade would be a feasible novel therapeutic strategy for acute sensory neural hearing loss.Neuroscience Research 12/2009; 66(4):345-52. · 2.25 Impact Factor -
Chapter: Immunobiology of IL-6 — Tocilizumab (humanised anti-IL-6 receptor antibody) for the treatment of rheumatoid arthritis
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ABSTRACT: The cloning of IL-6 cDNA in 1986 revealed that IL-6 is a multifunctional cytokine that plays important roles in the immunopathogenesis of rheumatoid arthritis (RA). A close relationship was observed between IL-6 levels in the synovial compartment and disease activity in RA patients, and overproduction of IL-6 could readily explain the abnormal laboratory findings and clinical symptoms seen in these patients. IL-6 therefore appeared to be a worthwhile and attractive therapeutic target for RA. In practice, blockage of IL-6 signalling by a humanised anti-IL-6 receptor antibody [tocilizumab (TCZ); also known as MRA] has been found to be very effective in the treatment of patients with RA. In recent Japanese Phase III clinical studies in RA patients, TCZ clearly prevented radiographic progression of joint destruction and greatly improved signs and symptoms. Very interestingly and importantly, this therapy has also proved quite effective at improving fever, fatigue and anaemia. No serious adverse events have been reported. At present, several international clinical studies of TCZ are ongoing in more than 4000 patients with active RA in 41 countries. The results are continuing to confirm the efficacy and safety of TCZ in the treatment of patients with RA.05/2009: pages 45-57; -
Article: Effects of interleukin-6 blockade on the development of autoimmune thyroiditis in nonobese diabetic mice.
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ABSTRACT: We explored the role of interleukin-6 (IL-6) in the development of autoimmune thyroiditis in nonobese diabetic (NOD) mice, an animal model of Hashimoto's thyroiditis, using anti-mouse IL-6 receptor antibody (MR16-1). Thyroiditis was induced by iodide ingestion or mouse thyroglobulin (Tg) immunization. Mice were injected intraperitoneally with saline, control rat IgG, or MR16-1 (2 or 8 mg). Iodide ingestion did not increase serum IL-6 levels and MR16-1 (2 mg) failed to prevent the development of thyroiditis. In contrast, Tg immunization induced a rapid and significant increase in serum IL-6 levels. While MR16-1 (2 mg) had no effect on Tg-induced thyroiditis, the severity, but not incidence, of thyroiditis was reduced in 8 mg MR16-1-treated mice compared with saline-injected mice. However, thyroiditis development in the 8 mg MR16-1-treated mice was indistinguishable from that in the control IgG-treated mice. MR16-1 (8 mg) did not affect serum anti-Tg antibody levels. These results suggest that IL-6 may play only a minor role in the development of autoimmune thyroiditis in NOD mice.Autoimmunity 04/2009; 42(3):228-34. · 2.47 Impact Factor -
Article: Involvement of Th17 cells and the effect of anti-IL-6 therapy in autoimmune uveitis.
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ABSTRACT: Human endogenous uveitis is one of the sight-threatening diseases associated with variety of systemic disorders, such as Behcet's disease and sarcoidosis. Recently, biosynthesized antibodies against inflammatory cytokines have been recognized to be useful to control the regional inflammation. In this study, we focused on the possibility of IL-6-based biological therapies for endogenous uveitis. We initially confirmed the significant increase of several inflammatory soluble factors including IL-6 in the vitreous fluids from refractory/chronic engogenous uveitis patients. To investigate the role of IL-6 in the formation of refractory ocular inflammation, we used the mouse experimental autoimmune uveitis (EAU) model. Both IL-6 and IL-23 are required for the development of IL-17-producing helper T subset (Th17) from naïve CD4(+) T cells. Results. In the EAU model, neither IL-6-deficient mice nor IL-23-deficient mice could induce Th17 cells and the EAU score was decreased in these mice in the entire time course. We also confirmed that systemic administration of anti-il-6 receptor antibody ameliorates EAU By suppressing both systemic and regional TH17 responses. IL-6 is responsible for causing ocular inflammation, and it is, at least partially, due to IL-6-dependent Th17 differentiation. IL-6 may be a target for therapy of refractory endogenous uveitis in humans.Rheumatology (Oxford, England) 02/2009; 48(4):347-54. · 4.24 Impact Factor -
Article: Interleukin-6 blockade suppresses autoimmune arthritis in mice by the inhibition of inflammatory Th17 responses.
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ABSTRACT: To investigate the mechanism of interleukin-6 (IL-6) blockade in autoimmune arthritis, by comparing the effect of anti-IL-6 receptor (anti-IL-6R) monoclonal antibody (mAb) treatment with the effect of soluble tumor necrosis factor (sTNFR)-Fc fusion protein treatment on T helper cell differentiation in collagen-induced arthritis (CIA). DBA/1 mice were immunized with type II collagen (CII) to induce arthritis and were left untreated or were treated with anti-IL-6R mAb or TNFR-Fc. T helper cell differentiation and cytokine expression during the development of arthritis in these mice were analyzed. Immunization with CII predominantly increased the frequency of Th17 cells rather than Th1 cells. The frequency of FoxP3+ Treg cells was also increased after immunization. Treatment of mice with CIA with anti-IL-6R mAb on day 0 markedly suppressed the induction of Th17 cells and arthritis development, but treatment with this antibody on day 14 failed to suppress both Th17 differentiation and arthritis. In contrast, treatment of mice with CIA with TNFR-Fc from day 0 to day 14 suppressed neither Th17 differentiation nor arthritis, but treatment from day 21 to day 35 successfully ameliorated arthritis without inhibiting Th17 induction. Neither antibody treatment increased the frequency of Treg cells. Our results indicate that the protective effect of IL-6 blockade, but not tumor necrosis factor (TNF) blockade, in CIA correlates with the inhibition of Th17 differentiation. Our findings suggest that IL-6 blockade in rheumatoid arthritis in human is also likely to involve a therapeutic mechanism distinct from that of TNF blockade and thus may represent an alternative therapy for patients in whom the disease is refractory to TNF blockade.Arthritis & Rheumatism 12/2008; 58(12):3710-9. · 7.87 Impact Factor -
Article: IL-6 blockade inhibits the induction of myelin antigen-specific Th17 cells and Th1 cells in experimental autoimmune encephalomyelitis.
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ABSTRACT: The development of Th17 cells is a key event in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a murine model of human multiple sclerosis (MS). Previous studies have demonstrated that an IL-6-dependent pathway is involved in the differentiation of Th17 cells from naïve CD4-positive T cells in vitro. However, the role of IL-6 in vivo in the development of Th17 cells in EAE has remained unclear. In the present study, we found that IL-6 blockade by treatment with an anti-IL-6 receptor monoclonal antibody (anti-IL-6R mAb) inhibited the development of EAE and inhibited the induction of myelin oligodendrocyte glycoprotein (MOG) peptide-specific CD4-positive, CD8-positive, and Th17 T cells, in inguinal lymph nodes. Thus, the protective effect of IL-6 blockade in EAE is likely to be mediated via the inhibition of the development of MOG-peptide-specific Th17 cells and Th1 cells, which in turn leads to reduced infiltration of T cells into the CNS. These findings indicate that anti-IL-6R mAb treatment might represent a novel therapy for human MS.Proceedings of the National Academy of Sciences 08/2008; 105(26):9041-6. · 9.68 Impact Factor -
Article: The recombinant humanized anti-IL-6 receptor antibody tocilizumab, an innovative drug for the treatment of rheumatoid arthritis.
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ABSTRACT: IL-6 is a pro-inflammatory cytokine with multiple roles in the pathogenesis of rheumatoid arthritis (RA). Targeting IL-6 with the humanized anti IL-6 receptor antibody tocilizumab was effective in several placebo-controlled clinical studies in RA. To address how clinically efficacious blockade of IL-6 signalling with inteleukin-6 receptor antibody is in RA patients and what the potential mode of action explaining tocilizumab activity in RA treatment could be. IL-6 induces autoantibody-producing plasma cells and effector T cells and is implicated in the development of clinical signs and symptoms, including increased synthesis of acute phase reactants, fatigue, anaemia and anorexia. Its effects also included significant improvements in American College of Rheumatology (ACR)20, ACR50 and ACR70 values, as well as in health-related quality of life measures, compared with controls. Tocilizumab also prevents radiographic progression of joint damage. Tocilizumab is generally well tolerated and efficacious in patients refractive to conventional DMARD therapies.Expert opinion on biological therapy 06/2008; 8(5):669-81. · 3.22 Impact Factor -
Article: Neuritogenic effects of T cell-derived IL-3 on mouse splenic sympathetic neurons in vivo.
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ABSTRACT: To determine the role played by lymphocytes and cytokines in the growth of sympathetic neurons in vivo, the innervation and cytokine levels were examined in the spleens of SCID mice that lack T and B cells. Splenic noradrenaline, nerve growth factor (NGF), and IL-1beta levels were elevated in SCID mice. Immunohistochemical examination revealed that the density of tyrosine hydroxylase-positive (TH(+)) fibers of splenic central arteries in SCID mice was increased compared with wild-type C.B-17 mice, while SCID mice had significantly fewer TH(+) fibers in their periarteriolar lymphatic sheaths (PALS). Two weeks after SCID mice were injected with C.B-17 splenic T cells, their TH(+) fiber staining increased in the PALS. IL-3 levels increased significantly in SCID mice following T cell reconstitution, and the administration of anti-IL-3 Ab blocked the above T cell-induced increase in innervation in the PALS. Anti-IL-3 treatment also inhibited the regeneration of splenic sympathetic neurons in C.B-17 mice after they were chemically sympathetomized with 6-hydroxydopamine. Depletion of NK cells by anti-asialo GM1 promoted the splenic innervation in SCID mice, while there were no significant changes in the innervation between CD8(+) T cell-deficient beta(2)-microglobulin knockout mice and their wild type. Our results suggest that T cells (probably CD4(+) Th cells but not CD8(+) CTLs) play a role in regulating the sympathetic innervation of the spleen; this effect appeared to be mediated, at least in part, by IL-3. On the contrary, NK cells may exert an inhibitory effect on the sympathetic innervation.The Journal of Immunology 04/2008; 180(6):4227-34. · 5.79 Impact Factor -
Article: Crucial role of the interleukin-6/interleukin-17 cytokine axis in the induction of arthritis by glucose-6-phosphate isomerase.
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ABSTRACT: To clarify the glucose-6-phosphate isomerase (GPI)-specific CD4+ T cell lineage involved in GPI-induced arthritis and to investigate their pathologic and regulatory roles in the induction of the disease. DBA/1 mice were immunized with GPI to induce arthritis. CD4+ T cells and antigen-presenting cells were cocultured with GPI, and cytokines in the supernatant were analyzed by enzyme-linked immunosorbent assay. Anti-interferon-gamma (anti-IFNgamma) monoclonal antibody (mAb), anti-interleukin-17 (anti-IL-17) mAb, or the murine IL-6 receptor (IL-6R) mAb MR16-1 was injected at different time points, and arthritis development was monitored visually. After MR16-1 was injected, percentages of Th1, Th2, Th17, and Treg cells were analyzed by flow cytometry, and CD4+ T cell proliferation was analyzed using carboxyfluorescein diacetate succinimidyl ester. GPI-specific CD4+ T cells were found to be differentiated to Th1 and Th17 cells, but not Th2 cells. Administration of anti-IL-17 mAb on day 7 significantly ameliorated arthritis (P < 0.01), whereas administration of anti-IFNgamma mAb exacerbated arthritis. Neither anti-IL-17 mAb nor anti-IFNgamma mAb administration on day 14 ameliorated arthritis. Administration of MR16-1 on day 0 or day 3 protected against arthritis induction, and MR16-1 administration on day 8 significantly ameliorated existing arthritis (P < 0.05). After administration of MR16-1, there was marked suppression of Th17 differentiation, without an increase in Th1, Th2, or Treg cells, and CD4+ T cell proliferation was also suppressed. IL-6 and Th17 play an essential role in GPI-induced arthritis. Since it has previously been shown that treatment with a humanized anti-IL-6R mAb has excellent effects in patients with rheumatoid arthritis (RA), we propose that the IL-6/IL-17 axis might also be involved in the generation of RA, especially in the early effector phase.Arthritis & Rheumatism 03/2008; 58(3):754-63. · 7.87 Impact Factor -
Article: Recent advances in immunopathophysiology of interleukin-6: an innovative therapeutic drug, tocilizumab (recombinant humanized anti-human interleukin-6 receptor antibody), unveils the mysterious etiology of immune-mediated inflammatory diseases.
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ABSTRACT: Interleukin (IL)-6 cDNA was originally cloned as a terminal B cell differentiation factor into antibody-producing plasma cells. This revealed that it is a multifunctional cytokine that acts on a variety of cells. From the clinical viewpoint, it is especially important that IL-6 acts on hepatocytes to induce acute-phase reactants, including C-reactive protein, serum amyloid A protein, and fibrinogen, and to decrease serum albumin levels. Very recently, this cytokine has been found to enhance the synthesis of a peptide called hepcidin in the liver which regulates iron recycling, resulting in anemia due to hypofferemia. It has also been shown that IL-6 is responsible for various clinical symptoms, including the appearance of autoantibodies, fatigue, anemia, anorexia, fever, and increases in the erythrocyte sedimentation rate, all of which develop in patients with various chronic autoimmune inflammatory diseases. In practice, blocking the IL-6 signaling pathway with a recombinant humanized anti-IL-6 receptor antibody, tocilizumab (TCZ), has dramatically improved all the signs and symptoms of these patients. A study in mice demonstrated that IL-6 promotes the development of a new type of T-helper cells called Th17 cells that impact the pathogenesis of autoimmune diseases. This suggests that TCZ is not only an antiinflammatory agent but also might affect basic autoimmunity. In this review, recent advances in the immunobiology of interleukin-6 related to immune-mediated diseases are discussed.Biological & Pharmaceutical Bulletin 12/2007; 30(11):2001-6. · 1.66 Impact Factor -
Article: Interleukin-6 receptor-mediated activation of signal transducer and activator of transcription-3 (STAT3) promotes choroidal neovascularization.
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ABSTRACT: Interleukin (IL)-6, a potent proinflammatory cytokine, is suggested to be a risk factor for choroidal neovascularization (CNV) because of its increased levels in the serum of patients with age-related macular degeneration; however, the role of IL-6 in CNV has not been defined. The present study reveals the critical contribution of IL-6 signaling and its downstream STAT3 pathway to the murine model of laser-induced CNV. CNV induction by laser treatment stimulated IL-6 expression in the retinal pigment epithelium-choroid complex, and antibody-based blockade of IL-6 receptor or genetic ablation of IL-6 led to significant suppression of CNV. CNV generation was accompanied by STAT3 activation in choroidal endothelial cells and macrophages, and IL-6 receptor blockade resulted in selectively inhibited phosphorylation of STAT3 but not extracellular signal-regulated kinase 1/2. Consistently, pharmacological blockade of STAT3 pathway also suppressed CNV. In addition, IL-6 receptor neutralization led to significant inhibition of the in vivo and in vitro expression of inflammation-related molecules including monocyte chemotactic protein, intercellular adhesion molecule-1, and vascular endothelial growth factor, and of macrophage infiltration into CNV. These results indicate the significant involvement of IL-6 receptor-mediated activation of STAT3 inflammatory pathway in CNV generation, suggesting the possibility of IL-6 receptor blockade as a therapeutic strategy to suppress CNV associated with age-related macular degeneration.American Journal Of Pathology 07/2007; 170(6):2149-58. · 4.89 Impact Factor -
Article: [Pharmacological and clinical profile of anti-human IL-6 receptor antibody (tocilizumab, ACTEMRA), a novel therapeutic drug for Castleman's disease].
Folia Pharmacologica Japonica 01/2006; 126(6):419-25. -
Article: Tocilizumab inhibits signal transduction mediated by both mIL-6R and sIL-6R, but not by the receptors of other members of IL-6 cytokine family.
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ABSTRACT: To characterize the biological activity of tocilizumab, a humanized anti-human interleukin-6 receptor (IL-6R) monoclonal antibody, we examined its binding activity to both soluble IL-6R (sIL-6R) and membrane bound IL-6R (mIL-6R) and its neutralizing activity to other IL-6 family cytokines. ELISA assay demonstrated that tocilizumab bound to sIL-6R and inhibited IL-6 binding to sIL-6R in a dose-dependent manner. The dissociation constant (Kd value) for IL-6R was determined to be 2.54+/-0.12 nmol/L by Scatchard analysis. In addition, tocilizumab had the ability to dissociate IL-6 and sIL-6R from their preformed complex. The immune complex of tocilizumab and sIL-6R did not transmit signaling. Moreover, tocilizumab suppressed the IL-6/sIL-6R complex-induced proliferation of human gp130-transfected cell, BAF-h130. In addition, tocilizumab had the ability to bind to human IL-6R expressing COS-7 cells and to suppress the growth of the IL-6-dependent myeloma cell line, KPMM2. Finally, to analyze the specificity of this antibody, the effects on signal transduction of IL-6 family cytokines such as interleukin-11 (IL-11), oncostatin M (OSM), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF) were examined using murine transfectant cell lines (BaF/IL-6R, BaF/IL-11R, BaF/OSMR, BaF/LIFR and BaF/CNTFR) that proliferate depending on IL-6, IL-11, OSM, LIF and human CNTF, respectively. Tocilizumab inhibited the proliferation of BaF/IL-6R induced by IL-6, but did not inhibit the proliferation of BaF/IL-11R, BaF/OSMR, BaF/LIFR and BaF/CNTFR cells induced by their corresponding cytokines. These lines of evidence indicate that tocilizumab is able to bind to both sIL-6R and mIL-6R and to inhibit IL-6 binding to its receptors, leading to the blockade of the IL-6 signaling through both sIL-6R and mIL-6R, but not block the signaling of other IL-6 family cytokines.International Immunopharmacology 12/2005; 5(12):1731-40. · 2.38 Impact Factor -
Article: Blockade of interleukin-6 signaling aggravates ischemic cerebral damage in mice: possible involvement of Stat3 activation in the protection of neurons.
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ABSTRACT: Interleukin (IL)-6 expression transiently increases in the acute phase of cerebral ischemia. To investigate the physiological significance of endogenous IL-6 expression and to identify the main signal pathway for the action of IL-6, we administered anti-mouse IL-6 receptor monoclonal antibody (IL-6RA), which blocks IL-6 signaling, to mice immediately after a 45-min period of middle cerebral artery occlusion (MCAO). At 6 h after MCAO, IL-6RA administration had resulted in a significant reduction in the amount of phosphorylated signal transducer and activator of transcription-3 (Stat3) protein in the peri-infarct area of the cortex. At 24 h after MCAO, blockade of IL-6 signaling had led to an increase in number of apoptotic cells in the peri-infarct area and enlargement of the size of the infarct, and it had adversely affected neurological function. These results suggest that endogenous IL-6 plays a critical role in preventing damaged neurons from undergoing apoptosis in the acute phase of cerebral ischemia and that its role may be mediated by Stat3 activation.Journal of Neurochemistry 08/2005; 94(2):459-68. · 4.06 Impact Factor -
Article: The therapy of autoimmune diseases by anti-interleukin-6 receptor antibody.
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ABSTRACT: Interleukin (IL)-6 plays essential roles not only in the immune response, but also in haematopoiesis and the central nervous system. Deregulated production of IL-6 has been found in chronic inflammatory autoimmune diseases, such as rheumatoid arthritis (RA), systemic onset juvenile idiopathic arthritis (soJIA), Crohn's disease (CD) and systemic lupus erythematosus (SLE). Furthermore, IL-6 activities can explain many symptoms of these diseases. More importantly, serum levels of IL-6 are correlated with disease activity. Based on these facts, the authors planned to develop a humanized anti-IL-6 receptor antibody, tocilizumab (previously known as MRA), as a therapeutic agent for these inflammatory autoimmune diseases. Tocilizumab is a neutralising antibody to suppress IL-6 signalling mediated by both membranous and soluble IL-6R. Clinical efficacy of tocilizumab in RA, soJIA, adult-onset Still's disease or CD patients has been discussed in this review. In all of these diseases, tocilizumab has improved the disease activity, suggesting that IL-6 plays an essential role in the pathogenesis of these diseases.Expert opinion on biological therapy 06/2005; 5(5):683-90. · 3.22 Impact Factor
Top co-authors
Top Journals
Institutions
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2008–2011
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National Institute of Biomedical Innovation
Ōsaka-shi, Osaka-fu, Japan
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2005–2010
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Keio University
- • Department of Rehabilitation Medicine
- • Department of Physiology
Tokyo, Tokyo-to, Japan
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2005–2008
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Chugai pharmceutical
Japan
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2003
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Osaka University
- Department of Health and Sport Sciences
Ibaraki, Osaka-fu, Japan
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